Question Sentinel/guide

Hi, what does Sentinel/guide means? I'm quite confuse. Can someone please enlighten me? I read the words in the comment section of Marshal, Please Calm down (https://chrysanthemumgarden.com/) I also read some in the forum of the same novel but i still don't get it. Thank you.

 

It’s a genre which I believe spawned from a single line in an obscure American TV show. It’s gained some popularity in fanfiction, and now in Chinese novels. I don’t think there’s any set rules as to what it entails, but it basically boils down to two people being bound together, with the emotionally sensitive guide helping the stronger sentinel remain sane.

 

https://fanlore.org/wiki/Sentinel_AU

Here’s a good description

 

It is kind of similar with Alpha and Omega, but you change it into Sentinel and Guide. It's also kind of different with omegaverse. Sentinel has a good physique, IQ, strong combat power. While guide is weak physique, and lovely appearance. Both guide and sentinel have a spiritual animal that comes from their mental power(?). Only fellow sentinel and guide can see each other's spiritual animal, and ordinary people can't see spiritual animal at all. All of their power are measured by their mental and physical power, and usually in many novels sentinel has a strong mental and physical power, while guide has strong mental but weak body. Because sentinel is too OP, they can get a mental problem that turns them crazy. Which why they need a guide to sooth them to avoid a mental mania. And they usually got pair up by the matching rate of the mental power. If the rate is too low, the guides can't sooth the sentinel's mental mania. And they got things like combine(?) Kind of similar with estrus (mating like a fuckin animal lmao). After they combined, they can feel each other's mental and physical state.